auto merge of #6195 : luqmana/rust/newtype-drop, r=catamorphism

Follow up with test case for #6125.

src/test/run-pass/newtype-struct-drop-run.rs

@@ -0,0 +1,28 @@
+// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// Make sure the destructor is run for newtype structs.
+
+struct Foo(@mut int);
+
+#[unsafe_destructor]
+impl Drop for Foo {
+    fn finalize(&self) {
+        ***self = 23;
+    }
+}
+
+fn main() {
+    let y = @mut 32;
+    {
+        let x = Foo(y);
+    }
+    assert_eq!(*y, 23);
+}